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# -*- coding: utf-8 -*-
""" PolymorphicManager
Please see README.rst or DOCS.rst or http://chrisglass.github.com/django_polymorphic/
"""
from __future__ import unicode_literals
import warnings
import django
from django.db import models
from polymorphic.query import PolymorphicQuerySet
class PolymorphicManager(models.Manager):
"""
Manager for PolymorphicModel
Usually not explicitly needed, except if a custom manager or
a custom queryset class is to be used.
"""
# Tell Django that related fields also need to use this manager:
use_for_related_fields = True
queryset_class = PolymorphicQuerySet
def __init__(self, queryset_class=None, *args, **kwrags):
# Up till polymorphic 0.4, the queryset class could be specified as parameter to __init__.
# However, this doesn't work for related managers which instantiate a new version of this class.
# Hence, for custom managers the new default is using the 'queryset_class' attribute at class level instead.
if queryset_class:
warnings.warn("Using PolymorphicManager(queryset_class=..) is deprecated; override the queryset_class attribute instead", DeprecationWarning)
# For backwards compatibility, still allow the parameter:
self.queryset_class = queryset_class
super(PolymorphicManager, self).__init__(*args, **kwrags)
def get_queryset(self):
return self.queryset_class(self.model, using=self._db)
# For Django 1.5
if django.VERSION < (1, 7):
get_query_set = get_queryset
# Proxy all unknown method calls to the queryset, so that its members are
# directly accessible as PolymorphicModel.objects.*
# The advantage of this method is that not yet known member functions of derived querysets will be proxied as well.
# We exclude any special functions (__) from this automatic proxying.
def __getattr__(self, name):
if name.startswith('__'):
return super(PolymorphicManager, self).__getattr__(self, name)
return getattr(self.get_queryset(), name)
def __unicode__(self):
return '%s (PolymorphicManager) using %s' % (self.__class__.__name__, self.queryset_class.__name__)
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